This is an application for partial funding of a meeting that is the third in a series of International Lymphokine Workshops. This year's theme will be "Lymphokines and Cytokines in Regulation". The Workshop will be held August 1-5, 1982 on the campus of Haverford College, which will provide a "closed" environment in an isolated suburban setting. The organizers of this event are Drs. Stanley Cohen and Joost Oppenheim, assisted by a Scientific Advisory Committee with international representation. It is anticipated that, as in the past, this meeting will help achieve new collective insights into the relationship of lymphokines to other regulatory macromolecules,and will foster discussions leading to unifying concepts regarding nomenclature, standardization of assays, etc. Most important, it will help to define and clarify new problems, directions, and approaches, not only with respect to regulation and control of lymphokine-dependent reaction, but also with respect to methodologies for further purifying and characterizing these important biologic mediators.